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Delta Electronics AC Motor Drive VFD-E User Manual

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Appendix D How to Use PLC Function|

Revision June 2008, 04EE, SW--PW V1.11/CTL V2.11

D-53

API Mnemonic Operands

Function

21

SUB P

S

1

, S

2

,

D Subtraction

Bit Devices

Word devices

Program Steps

Type
OP

X Y M K H

KnX KnY KnM T

C

D

S

1

*

*

*

*

*

*

*

*

S

2

*

*

*

*

*

*

*

*

D

*

*

*

*

*

SUB, SUBP: 7 steps
DSUB, DSUBP: 13 steps

Operands:

S1: Minuend S2: Subtrahend D: Remainder

Explanations:

1.

This instruction subtracts S1 and S2 in BIN format and stores the result in D.

2.

The highest bit is symbolic bit 0 (+) and 1 (-), which is suitable for algebraic subtraction.

3.

Flag changes in binary subtraction

In 16-bit instruction:

A. If the operation result = 0, zero flag M1020 = On.

B. If the operation result < -32,768, borrow flag M1021 = On.

C. If the operation result > 32,767, carry flag M1022 = On.

Program Example:

In 16-bit BIN subtraction:

When X0 = On, the content in D0 will minus the content in D10 and the remainder will be stored in

D20.

X0

SUB

D0

D10

D20